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Can Holter monitor findings predict the results of electrophysiologic studies?
1094
JACC Vol. 5, No.5 May 1985: 1094
Editorial Comment
Can Holter Monitor Findings Predict the Results of Electrophysiologic Studies?* GARYJ.ANDERSON,MD,FACC Philadelphia. Pennsylvania
The number of published reports describing sudden death victims has been rapidly expanding, with regard to both prevention and prediction of sudden death. The latter is of paramount importance because without the ability to predict, attempts for prevention remain empirical. Anatomic and hemodynamic predictors of sudden death candidates have been advanced and include severe coronary disease and recurrent myocardial infarction, low left ventricular ejection fraction and hemodynamic instability when ventricular arrhythmias occur. Although these correlations are useful, the clinical electrophysiologic laboratory seems to have ascended to a position of "the definitive test" since electrophysiologically provoked ventricular tachycardia and fibrillation correlate well with the finding of spontaneous ventricular arrhythmias. Moreover, the conventional, noninvasive assessment by electrocardiogram and Holter ambulatory monitoring has not been as successful as desired for predicting serious arrhythmias or correlating with electrophysiologically provoked arrhythmias. In this issue of the Journal, Gradman et al. (I) examined the correlation between Holter monitor findings and the results from programmed electrical stimulation. Their results are encouraging and shed new light on this complex subject. This study was conducted on 48 patients, of whom 23 had not received antiarrhythmic drugs for 48 hours and 10 had not received drugs for at least 24 hours. The authors emphasized that many unsuccessful attempts to correlate Holter monitor findings with inducibility of ventricular tachycardia were based on patients maintained on antiarrhythmic therapy. The authors showed that in their study certain Holter monitor findings did correlate with inducibility. They were: I) frequency of ventricular premature beats of 100 or morell ,000 normal beats, 2) mean couplet frequency of I or morell ,000 normal beats, and 3) a mean repetition index of 15 or morell,OOO premature beat com*Editorials published in Journal ofthe American College ofCardiology reflect the views of the authors and do not necessarily represent the opinions of JACC or the American College of Cardiology. From the Likoff Cardiovascular Institute. Hahnemann University School of Medicine. Philadelphia, Pennsylvania. Address for reprints: Gary J. Anderson. MD. Likoff Cardiovascular Institute, Hahnemann University School of Medicine, Broad and Vine Streets, Philadelphia, Pennsylvania 19102-1192. © 1985 by the American College of Cardiology
plexes. In addition, patients whose arrhythmia was noninducible had a low incidence of spontaneous ventricular tachycardia (11%) during Holter monitoring as compared with those with induced sustained ventricular tachycardia (78%).
These findings are interesting and deserve comment because of the potential existence of a correlation between Holter monitor findings and programmed stimulation in predominantly untreated patients. A provocative point raised by the report of Gradman et al. is the question of the clinical meaning of "severity" or "complexity" of ventricular arrhythmias. While multiformity and couplets are considered "complex," the frequency or prevalence of these beats is often not taken into account. Multiformity of premature ventricular beats did not discriminate between the patients with inducible or noninducible ventricular tachycardia, although the prevalence of multiformity increased with inducibility. The repetition index (that is, the ratio of ventricular couplets to premature ventricular beats) did correlate well. Perhaps this correlation, while innovative, is a logical extension of reason. It simply addresses the probability that a premature ventricular couplet will be followed by another. It is not surprising then that the ratio of couplets to premature ventricular beats would correlate with spontaneous or induced ventricular tachycardia since all one needs is "one more repetition" in a couplet to produce ventricular tachycardia. If premature ventricular couplets are never associated with repetitive phenomena and are frequent, the absence of ventricular tachycardia is likely. Conversely, if infrequent premature ventricular couplets are followed by another premature ventricular couplet 50% of the time, then the repetition index is high. Therefore, the probability of ventricular tachycardia would be presumably higher. These correlations are not bold or daring. They represent the required continued attempts to find correlates of induced and spontaneous ventricular arrhythmia from cheaper and more readily obtained techniques. The impact is potentially great. However, a word of caution issued by Gradman et al. needs reiteration. It is tempting to assume that the Holter monitor findings described have a universal application, but such an association is an oversimplification. The clinician must recognize that the select patients reported in such a study are unique and not representative of an average group of patients studied by Holter monitoring. The significance of a high repetition index in an otherwise nonselected group of patients is unknown at present and deserves further study.
Reference 1. Gradman AH. Batsford WP. Rieur EC. Leon L, Van Zelia AM. Ambulatory electrocardiographic correlates of ventricular inducibility during programmed electrical stimulation. J Am Coli Cardiol 1985;5: 1087-93. 0735-1097/85/$3.30
JACC Vol. 5, No.5 May 1985: 1094
Editorial Comment
Can Holter Monitor Findings Predict the Results of Electrophysiologic Studies?* GARYJ.ANDERSON,MD,FACC Philadelphia. Pennsylvania
The number of published reports describing sudden death victims has been rapidly expanding, with regard to both prevention and prediction of sudden death. The latter is of paramount importance because without the ability to predict, attempts for prevention remain empirical. Anatomic and hemodynamic predictors of sudden death candidates have been advanced and include severe coronary disease and recurrent myocardial infarction, low left ventricular ejection fraction and hemodynamic instability when ventricular arrhythmias occur. Although these correlations are useful, the clinical electrophysiologic laboratory seems to have ascended to a position of "the definitive test" since electrophysiologically provoked ventricular tachycardia and fibrillation correlate well with the finding of spontaneous ventricular arrhythmias. Moreover, the conventional, noninvasive assessment by electrocardiogram and Holter ambulatory monitoring has not been as successful as desired for predicting serious arrhythmias or correlating with electrophysiologically provoked arrhythmias. In this issue of the Journal, Gradman et al. (I) examined the correlation between Holter monitor findings and the results from programmed electrical stimulation. Their results are encouraging and shed new light on this complex subject. This study was conducted on 48 patients, of whom 23 had not received antiarrhythmic drugs for 48 hours and 10 had not received drugs for at least 24 hours. The authors emphasized that many unsuccessful attempts to correlate Holter monitor findings with inducibility of ventricular tachycardia were based on patients maintained on antiarrhythmic therapy. The authors showed that in their study certain Holter monitor findings did correlate with inducibility. They were: I) frequency of ventricular premature beats of 100 or morell ,000 normal beats, 2) mean couplet frequency of I or morell ,000 normal beats, and 3) a mean repetition index of 15 or morell,OOO premature beat com*Editorials published in Journal ofthe American College ofCardiology reflect the views of the authors and do not necessarily represent the opinions of JACC or the American College of Cardiology. From the Likoff Cardiovascular Institute. Hahnemann University School of Medicine. Philadelphia, Pennsylvania. Address for reprints: Gary J. Anderson. MD. Likoff Cardiovascular Institute, Hahnemann University School of Medicine, Broad and Vine Streets, Philadelphia, Pennsylvania 19102-1192. © 1985 by the American College of Cardiology
plexes. In addition, patients whose arrhythmia was noninducible had a low incidence of spontaneous ventricular tachycardia (11%) during Holter monitoring as compared with those with induced sustained ventricular tachycardia (78%).
These findings are interesting and deserve comment because of the potential existence of a correlation between Holter monitor findings and programmed stimulation in predominantly untreated patients. A provocative point raised by the report of Gradman et al. is the question of the clinical meaning of "severity" or "complexity" of ventricular arrhythmias. While multiformity and couplets are considered "complex," the frequency or prevalence of these beats is often not taken into account. Multiformity of premature ventricular beats did not discriminate between the patients with inducible or noninducible ventricular tachycardia, although the prevalence of multiformity increased with inducibility. The repetition index (that is, the ratio of ventricular couplets to premature ventricular beats) did correlate well. Perhaps this correlation, while innovative, is a logical extension of reason. It simply addresses the probability that a premature ventricular couplet will be followed by another. It is not surprising then that the ratio of couplets to premature ventricular beats would correlate with spontaneous or induced ventricular tachycardia since all one needs is "one more repetition" in a couplet to produce ventricular tachycardia. If premature ventricular couplets are never associated with repetitive phenomena and are frequent, the absence of ventricular tachycardia is likely. Conversely, if infrequent premature ventricular couplets are followed by another premature ventricular couplet 50% of the time, then the repetition index is high. Therefore, the probability of ventricular tachycardia would be presumably higher. These correlations are not bold or daring. They represent the required continued attempts to find correlates of induced and spontaneous ventricular arrhythmia from cheaper and more readily obtained techniques. The impact is potentially great. However, a word of caution issued by Gradman et al. needs reiteration. It is tempting to assume that the Holter monitor findings described have a universal application, but such an association is an oversimplification. The clinician must recognize that the select patients reported in such a study are unique and not representative of an average group of patients studied by Holter monitoring. The significance of a high repetition index in an otherwise nonselected group of patients is unknown at present and deserves further study.
Reference 1. Gradman AH. Batsford WP. Rieur EC. Leon L, Van Zelia AM. Ambulatory electrocardiographic correlates of ventricular inducibility during programmed electrical stimulation. J Am Coli Cardiol 1985;5: 1087-93. 0735-1097/85/$3.30